Peripheral Vascular Noninvasive Measurements

Abstract

Assessment of physiological and pathological parameters of the peripheral vasculature is important for the diagnosis and monitoring of vascular diseases, many of which can evolve into severe or even life‐threatening conditions. There is great desire for noninvasive measurement methods as alternatives or adjuncts to available invasive techniques, which often are limited in their use because of patient risk, operating complexity, or cost. The first part of the article gives a broad overview of existing noninvasive techniques for the evaluation of vascular parameters such as pressure, flow, and compliance. For each method, a general introduction is given followed by the theoretical framework of signal generation and device implementation. This is complemented by descriptions of signal analysis and clinical applications. The second part of the article briefly reviews of how available imaging‐based methods relate to the evaluation of the vasculature, including a number of advanced techniques that are presently in development or are undergoing clinical or preclinical trials.

Comparative study of methodologies for pulse wave velocity estimation

“…The pressure wave can be recorded directly by means of force recorders, such as highfidelity applanation tonometers [14][15][16][17] or by detecting arterial wall motion secondary to pulse pressure by means of mechanotransducers or ultrasonographic systems. [18][19][20][21][22] A surrogate of PWV, the stiffness index (SI), has also been proposed by assessing capillary consequences of arterial stiffness using photoplethysmography, although some studies have showed a feeble correlation between SI and carotid-femoral PWV (PWV cÀf ). [23][24][25] The calculation of propagation time can be measured by various means, including analyzing the foot of the pulse wave, the points of maximum upslope or peak-to-peak time.…”

Optomechanical imaging system for breast cancer detection

“…In recent years, our group has emphasized the added value of recording dynamic elements of tissue optical contrast that may naturally occur (e.g., natural beat frequencies associated with the vascular tree) or can be introduced through controlled manipulations [18][19][20]. By enabling highdensity dynamic optical measures of the breast combined with concurrent viscoelastic measures explored through precise articulation, our goal here has been to capture the key elements of both strategies as a means for improved detection of breast cancer.…”

“…The other approach is to define dynamic responses of the tissue based on measures of relative changes in the optical signal [16,17]. While not easily supporting absolute constituent measures, this approach has the added benefit of exploring any of a host of dynamic features associated with Hb signals that may occur spontaneously (e.g., vascular rhythms) [18] or can be induced by controlled provocations [19,20]. In a previous report, we described a system that can dynamically image both breasts simultaneously and provided evidence of enhanced tumor detection from a simple respiratory maneuver [21].…”

Quantitative Analysis of Mental Effort Investment using Photoplethysmogram

“…Photoplethysmogram (PPG) is an optical measurement technique that can be used to detect blood volume changes in the microvascular bed of tissue (Allen, 2007;Alneab et al, 2007). The pulse wave analysis (PWA) of photoplethysmogram provides lots of circulatory information including but not limited to the pulse amplitude (Schmitz et al, 2006). Goor et al (Goor et al, 2004) has demonstrated that the mental-stress induced peripheral arterial vasoconstriction predicts mentalstress-induced myocardial ischemia.…”